A novel hollow microsphere composite MnOx/PAA: effective catalyst for ozone decomposition at high humidity

Ozone air pollution poses a serious threat to human health and ecological environment. Manganese oxide (MnOx) is a popular material for ozone decomposition with excellent catalytic performance. However, the catalytic activity may be reduced under high-humidity conditions because of oxygen vacancy of MnOx from the water evaporation. In this paper, a new type of MnOx/poly(acrylic acid-co-divinylbenzene) (PAA) catalyst with MnOx supported on hollow PAA was successfully prepared, which greatly improved the ozone decomposition efficiency under high humidity. It was shown that when the acrylic acid (AA) content was more than 50%, the PAA polymer layer was hydrophilic and the ozone decomposition efficiency would keep high activity for both the low- and high-humidity conditions. The best performance of ozone decomposition was identified for the methanol reduction and AA content of 60%, in which the efficiencies reached 94.5% and 85% at 50% and 90% humidity levels, respectively. It is the synergetic effect of the hydrophilic PAA support and hollow structure that retains and improves the decomposition activity, which can absorb the water vapor molecules and increase the ozone retention time. Therefore, the hollow microsphere catalyst prepared in this paper has great potential in solving the problem of ozone air pollution.